NEC mPD780852 Series Preliminary User's Manual page 167

(8) Interrupt request flag (ADIF)
The interrupt request flag (ADIF) is not cleared even if the analog input channel specification register (ADS1)
is changed.
Caution is therefore required since, if a change of analog input pin is performed during A/D conversion, the
A/D conversion result and conversion end interrupt request flag for the pre-change analog input may be set just
before the ADS1 rewrite, and when ADIF is read immediately after the ADS1 rewrite, ADIF may be set despite
the fact that the A/D conversion for the post-change analog input has not ended.
When the A/D conversion is stopped and then resumed, clear ADIF before the A/D conversion operation is
resumed.
Figure 12-12. A/D Conversion End Interrupt Request Generation Timing
ADS1 rewrite
(start of ANIn conversion)
A/D conversion
ADCR1
INTAD
Remarks 1. n = 0, 1, ..., 4
2. m = 0, 1, ..., 4
(9) Read of A/D conversion result register (ADCR1)
When write operation is executed to A/D converter mode register (ADM1) and analog input channel specification
register (ADS1), the contents of ADCR1 are undefined. Read the conversion result before write operation is
executed to ADM1, ADS1. If a timing other than the above is used, the correct conversion result may not be
read.
CHAPTER 12 A/D CONVERTER
ADS1 rewrite
(start of ANIm conversion)
ANIn ANIn
ANIn
Preliminary User's Manual U14581EJ3V0UM00
ADIF is set but ANIm conversion
has not ended.
ANIm ANIm
ANIn ANIm ANIm
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